Different shape notches effects on tearing del-zone for stratospheric airship envelope material

Stratosphere airship envelope material is composed of multilayer laminated film material reinforced by fiber. As the same as other film material, it occurs del-zone in the course of crack tearing propagation, which is significant for envelope material mechanic studies. Many researched unlined its application, not it’s forming factors. The paper focus on crack or notch shape effects on the del-zone. Six groups test including specimen with no crack, central crack, square notch, diamond notch, circle notch, and rectangle notch are carried on under the stretching instrument to find the different del-zone phenomenon and get displacement-load curve. Combined with theory, the paper try to explain the del-zone differences for specimens and explore the shape notched sensitivity to specimen. The results shows that different specimen have differences on del-zone, further affecting the specimen module and fracture strength. In turn, it manifests that to some extent, the size del-zone decides fracture stress value, providing advice for airship envelope designing.